Go to the start page of www.caraudio.com and search the on-line stores to get a good idea of what a good price is for your list of equipment. Just remember that retail store prices are a lot more than the internet prices. As for install, here is basic lay down of BASIC install prices - 2 channel amp = $55, 4 channel amp = $65-$100, subs in box = $25 (per pair), Components = $30 - $75. Add an additional $50 - $100 for wiring. Also, as just a suggestion, don't go for the high cost components for the rear, just use some decent coaxial speakers. The rear is just for fill so spending big $$$ on components for the rear is not really necessary.

Learning how to put your own system in is the best move you can ever make. But I do understand what it is like to be new to the car audio world. Try www.cbrstereo.com or www.onlinecarstereo.com .
If you find all your equipment there, add it up. Then add about $100 for shipping and $300-400 for parts and labor. Make sure the shop, with install, can come close to that. They won't be able to touch the equipment prices because they have more overhead to worry about, but DEMAND a big discount in installation costs to compensate.